In recent years, high levels of safety performance of vehicles have been required. This trend is shared across countries around the world where most vehicles are currently standard-equipped with airbags as vehicle safety devices. Firms involved in vehicle development have adopted ongoing safety improvement as a major development guideline. In keeping with this, new airbags are continually being developed.
Standards for evaluating vehicle safety differ from country to country, and firms approach product development such that products can meet evaluation standards in multiple countries. In the United States, for instance, which has the largest automobile fleet in the world Federal Motor Vehicle Safety Standards (FMVSS) are issued by the National Highway Traffic Safety Administration (NHTSA). In a Notice of Proposed Rulemaking (NPRM) for FMVSS, a requirement is proposed that aims at “reducing the probability of occupant ejection from a vehicle through a side window using an ejection mitigation system in the event of a side impact or rollover”. The requirement can be met by providing a side curtain airbag as a device intended to reduce ejection from a vehicle, such that the side curtain airbag constitutes the ejection mitigation system.
The curtain airbag for the vehicle is installed at the upper end in the vehicle so as to inflate and deploy upon a vehicle collision. The side curtain airbag provides high levels of safety performance upon a rollover as well as a side impact collision of the vehicle.
Meanwhile, for the protection of the occupant, a driver seat airbag is designed as most often a round bag and in the inflated state covers the steering wheel, is further provided in the steering wheel of the vehicle as well. As the steering wheel naturally is arranged to perform a rotational movement, with a steering wheel hub not being fixed the airbag as well performs this rotational movement, so that the airbag itself needs to be deigned to be symmetric and in particular to be round, in order that it can fulfill its protective function independent of the position of the steering wheel.
In the event of an accident, during the occurring forward movement the occupant generally is protected by the curtain airbag and the driver seat airbag. Upon a vehicle collision, the head of the occupant collides with the driver seat airbag and may be inserted into a gap between the curtain airbag and the driver seat airbag.